The present invention relates generally to pressure measuring and regulating devices and method, and in particular to a device for and a method of measuring and regulating the pressure within an inflatable cuff forming a part of a medical apparatus.
During certain types of surgical procedures, by way of example, anesthetic is administered to a patient by using an endotracheal tube having an inflatable cuff which is inflated by a source of pressurized air. When the cuff is properly inflated, the endotracheal tube is restrained against slippage by the pressure of the cuff against the mucosal wall of the trachea.
However, even though the cuff is made from materials impervious to air, certain types of anesthetics are capable of passing through the walls of the cuff, thereby increasing the gas pressure therein. Often this increase in gas pressure exerted by the over-inflated cuff of the endotracheal tube can result in damage to the mucosal wall of the trachea, which in some instances may be irreversible. Consequently, it is extremely important that the cuff pressure be maintained at a minimum value, e.g. approximately 25 mmHg.
In order to monitor the cuff pressure, mechanical or mercury manometers have heretofore been used. These devices are frequently cumbersome due to their size and occupy valuable space within the operating room, recovery room or even in a patient's room. Moreover, such manometers contain a large amount of dead air space in the connecting tube, and hence the readings are frequently inaccurate.